Problem: $\dfrac{3}{4} + \dfrac{1}{5} = {?}$
Answer: ${\dfrac{3}{4}}$ ${\dfrac{1}{5}}$ $+$ ${\dfrac{3 \times 5}{4 \times 5}}$ ${\dfrac{1 \times 4}{5 \times 4}}$ $+$ ${\dfrac{15}{20}}$ ${\dfrac{4}{20}}$ $+$ $ = \dfrac{{15} + {4}}{20} $ $ = \dfrac{19}{20}$